Chromatographic analysis method and apparatus therefor



March 12, 1968 R. A. SANFORD ET AL 3,372,573

CHROMATOGRAPHIC ANALYSIS METHOD AND APPARATUS THEREFOR Filed Feb. 24,1954 .lu'lbll INVENTORS RA. SANFORD J.S. CALHOUN mN mOPUuFwQ Owmm A TTORNE' rs United States Patent 3,372,573 CHROMATOGRAPHIC ANALYSIS METHODAND APPARATUS THEREFOR Richard A. Sanford and James S. Calhoun,Bartlesvrlle,

Okla, assignors to Phillips Petroleum Company, a corporation of DelawareFiied Feb. 24, 1964, Ser. No. 346,783 6 Claims. (Cl. 73-231) ABSTRACT OFTHE DISQLOURE A valving system having three control units which, forexample, operate sequentially to entrap a sample of a liquid containingnon-volatile materials in a sample loop; flush vaporized components ofthe liquid sample from the sample loop; flush solvent through the sampleloop to extract non-volatile components therefrom; and pass drying gasthrough the sample loop to thereby yield a dry sample loop containing noclogging deposits therein.

This invention relates to an improved chromatographic method of analysisand apparatus therefor. In another aspect, this invention relates to achromatographic method of analysis and apparatus therefor wherein thesample feed to the chromatographic analyzer contains a nonvolatileconstituent.

A conventional method for the determination of the concentration ofconstituents in a fluid involves the use of a chromatogrhphic analyzer.in chromatography, a sample of the material to be analyzed is introducedinto a column containing a selective sorbent or partitioning material. Acarrier gas is directed into the column so as to force the samplematerial therethrough. The selective sorbent, or partitioning material,attempts to hold the constituents of the material. This results in theseveral constituents of the fluid mixture flowing through the column atdifferent rates of speed, depending upon their afiinities for thepacking material. The column effluent thus consists initially of thecarrier gas alone, the individual constituents of the fluid mixtureappearing later at spaced time intervals. A conventional method ofdetecting the presence and concentration of these constituents is toemploy a thermal conductivity detector which compares the thermalconductivity of the column effiuent gas with the thermal conductivity ofthe carrier gas directed to the column.

A conventional vaporous chromatographic analyzer cannot be employed forliquid samples containing soluble nonvolative constituents. Thesenonvolatile constituents upon vaporization of the liquid sample willbecome deposited in the sample valve and the lines of thechromatographic analyzer. This results in valve stoppage and pluggedlines, substantially changing the operation of the chromatographiccolumn.

Accordingly, an object of our invention is to provide an improvedchromatographic method of analysis and apparatus therefor.

Another object of our invention is to provide a chromatographic methodof analysis and apparatus therefor wherein a"liquid to be analyzedcontains a nonvolatile soluble constituent.

Another object of our invention is to provide an improved method andapparatus for obtaining a vaporous sample for introduction into achromatographic column from a liquid containing a soluble nonvolatileconstituent.

Other. objects, advantages and features of our invention will be readilyapparent to those skilled in the art from the following description, thedrawing and appended claims.

By our invention, we have provided a chromatographic method of analysisand apparatus therefor wherein a liquid containing a soluble nonvolatileconstituent is passed to a sample zone; a carrier gas is passed to saidsampling zone and from said sampling zone to a chromatographic column; awash liquid is passed through said sampling zone; and a drying gas ispassed through said sampling zone.

FIGURES 1, 2, 3 and 4 illustrate schematically one embodiment of theinvention.

Referring to the drawing, therein is illustrated a chromatographiccolumn 27, a detector 29, conduits 26, 28 and 3t), and a sample zone 9containing valves 10, 11 and 12, said valves positioned during the fourstages of the inventive analysis procedure as illustrated in FIGURES l,2, 3 and 4, respectively.

Referring to FIGURE 1, valves 10, 11 and 12 can be conventionalmulti-port valves containing multiple interconnecting passages such asdescribed in US. Patent 3,- 095,746. As illustrated, valve 10 contains asample loop 16 and ports 1, 2, 3, 4, 5 and 6. Valve 11 contains ports1', 2, 3, 4, 5' and 6' and valve 12 contains ports 1", 2", 3", 4", 5"and 6". It can readily be seen by referring to FIGURES 1, 2, 3 and 4that it is within the'scope of this invention to employ in place ofvalve 12 a valve having less than 6 ports with interconnecting passages.

Valves 1t), 11 and 12 can be operated by a timer 15. This timer can beany type of apparatus known in the art for providing control signals ina desired sequence and positioning valves 10, 11 and 12 in the positionsillustrated by FIGURES 1, 2, 3 and 4. The common type of timer utilizesa series of cam operated switches wherein the associated cams arerotated by a timing motor.

In the first stage as illustrated by FIGURE 1, a sample liquid feedcontaining a soluble nonvolatile constituent is passed via conduit means13 to valve 10 and through conduit 14 within valve 10 to sample loop 16.With a continuous sample feed to valve 10, the sample passes from sampleloop 16 through valve 10 via conduit 17 and from valve 10 via conduitmeans 18.

An inert carrier gas such as helium is passed via conduit means 24 tovalve 11, through valve 11 via conduit 21, and from valve 11 to valve 10via conduit means 20. The carrier gas is passed through valve 10 viaconduit 19 and from valve 10 to valve 11 via conduit means 22. Asillustrated, the carrier gas is passed through valve 11 via conduit 23and from valve 11 to column 27 via conduit means 26. The carrier gas iswithdrawn from column 27 via conduit means 28, passed through detector29, and withdrawn from detector 29 via conduit means 30.

Column 27 is filled with a packing material which selectively retardsthe passage therethrough of constituents of a fluid sample mixture to beanalyzed. Detector 29" can be a thermal conductivity detector whichincludes a temperature-sensitive resistant element placed in the path offluid flow. A reference element, not shown, can be placed in the carriergas flow. This detector provides signals representative of thedifference in thermal conductivity be tween the column efiluent and thecarrier gas. The temperature differences between the resistance elementscan be measured by electrical bridge circuits, such as a Wheatstonebridge, for example. It is, of course, within the skill of the art toemploy other means of detecting the concentration of constituents in asample fluid than the thermal conductivity detector herein described.

A wash solvent is passed via conduit means 38 to valve 12 and throughvalve 12 via conduit 36. The wash solvent must be a liquid capable ofremoving the nonvolatile constituents contained in the sample liquidpassed to valve 10. The wash solvent is passed from valve 12 to valve 11via conduit means 33, throughvalve 11 via conduit 31 and withdrawn fromvalve 11 via conduit means 32.

After completion of the first stage and upon positioning valves 10, 11and 12 for the second stage as illustrated in FIGURE 2, the sampleliquid containing a soluble nonvolatile constituent is passed viaconduit means 13 to valve 10, through valve via conduit 39 and withdrawnfrom valve 10 via conduit means 18. The carrier gas is passed aspreviously described via conduit means 24 to valve means 11, throughvalve means 11 via conduit 21, and from valve 11 to valve 10 via conduitmeans 20. During the second stage, the carrier gas is directed throughvalve 10 via conduit means 42. The sample liquid within sample loop 16is vaporized by the carrier gas and is passed from valve 10 to valve 11in the carrier gas via conduit means 43 and 22. The nonvolatileconstituent or constituents remain in sample loop 16. The carrier samplecontaining the volatilized sample is passed through valve 11 via conduitmeans 23 and from valve 11 via conduit means 26. The carrier gascontaining the volatilized sample is passed into column 27. An effluentis withdrawn from column 27 via conduit means 28, passed to detectormeans 29 wherein the concentration of sample constituents is determinedand withdrawn from detector 29 via conduit means 30.

In the second stage, a wash solvent is passed via conduit means 38 tovalve 12, through valve 12 via conduit means 36, and from valve 12 tovalve 11 via conduit means 33. The wash solvent is passed through valve11 via conduit 31 and withdrawn from valve 11 via conduit means 32.

In the third stage and after completion of the second stage operation,illustrated in FIGURE 3, the sample liquid is passed via conduit means13 to valve 10, through valve 10 via conduit 39 and withdrawn from valve10 via conduit means 18. The carrier gas is passed through a conduitmeans 24 to valve 11, through valve 11 via conduit 40, and from valve 11to column 27 via conduit means 26. The carrier gas is passed throughcolumn 27 and through detector 29 via conduit means 28 and 30.

In the third stage, the carrier gas is passed via conduit means 37 toport 6" of valve 12 and through valve 12 via conduit 41 to port 1". Thewash solvent contained in conduit means 33 is passed by means of thecarrier gas through valve 11 via conduit 44 and from valve 11 to valve10 via conduit means 22. The wash solvent is passed through conduit 43and sample loop 16 of valve 10, thereby removing any nonvolatileconstituents contained within conduits 22, 43 and sample loop 16. Thewash solvent employed must be capable of dissolving the nonvolatileconstituents contained in the sample liquid feed. The wash solvent iswithdrawn from valve 10 via conduit 42 and conduit means 20, and passedthrough valve 11 via conduit 46 and conduit means 32. After removal ofthe wash solvent from the chromatographic system is complete, thepassage of carrier gas via conduit means 37, through valve 12 viaconduit 41, and from valve 12 to valve 11 and 10 in the previouslydescribed manner for the third stage, operates to dry the valve andinterconnecting conduits so as to remove any traces of wash solventtherefrom. The carrier or drying gas is passed to valve 12 via conduitmeans 37 and can be the same or different than the carrier gas passedvia conduit means 24 to valve means 11.

In the fourth stage, the sample liquid is passed via conduit means 13 tovalve 10 and to sample loop 16 contained within valve 10 via conduit 14.The sample liquid is withdrawn from valve 10 via conduit 17 and conduitmeans 18. A drying gas is passed via conduit means 37 to valve 12,through valve 12 via conduit 41, and from valve 12 to valve 11 viaconduit means 33. The drying gas is passed through valve 11 via conduit44 and from valve 11 to valve 10 via conduit means 22. The drying gas ispassed through valve 10 via conduit 19, from valve 10 to valve 11 viaconduit means 20, and from valve 11 via conduit 46 and conduit means 32.The sampling zone or system is thus washed free of any nonvolatileconstituents contained therein and thoroughly dried prior to the passageof a second measured sample to chromatographic column 27. During thefourth stage, the carrier gas is passed as previously described viaconduit means 24 to valve 11, through valve 11 via conduit 40 and fromvalve 11 to column 27 via conduit means 26.

Although not to be limited thereto, the invention has been found to beparticularly applicable to the analysis of ethyl alcohol in waterwherein the water also contains nonvolatile sugars and other organicconstituents. When applied to the analysis of ethyl alcohol and water, apreferred cycle time of four minutes has been found to be particularlyeffective to complete the sampling, analysis, Washing and drying steps.Valves, 10, 11 and 12 were maintained in the first stage for about 2percent of the cycle time, in the second stage for about 18 percent ofthe cycle time, in the third stage for about 35 percent of the cycletime, and in the fourth stage for the remainder of the cycle time.

As will be evident to those skilled in the art, various modifications ofthis invention can be made, or followed, in the light of the foregoingdisclosure, without departing from the spirit or scope thereof.

We claim:

1. A chromatographic valving apparatus comprising a first, second andthird valve means, each of said first, second and third valve meanscontaining multiple ports and interconnecting passages, said first valvemeans containing a sampling means, first conduit means communicatingwith said first valve means for passing sample fluid thereto, secondconduit means communicating with said first valve means for withdrawingsample fluid therefrom, third conduit means communicating between saidsecond valve means and said first valve means, fourth conduit meanscommunicating between said first valve means and said second valvemeans, fifth conduit means communicating with said second valve meansfor passing a first carrier gas stream thereto, sixth conduit meanscommunicating with said second valve means for passing sample fluid andcarrier gas therefrom, seventh conduit means communicating with saidsecond valve means for withdrawing carrier gas and wash fluid therefrom,eighth conduit means communicating bet-ween said second valve means andsaid third valve means, ninth conduit means communicating with saidthird value means for passing a second carrier gas stream thereto, tenthconduit means communicating with said third valve means for passing awash fluid thereto, each of said valve means having a first and secondvalve positions, with each of said first, second and third valve meansin said first valve position,

(1) passage means communicating between said first conduit means andsaid sampling means,

(2) passage means communicating between said sampling means and saidsecond conduit means,

(3) passage means communicating between said fifth conduit means andsaid third conduit means,

(4) passage means communicating between said third and fourth conduitmeans,

(5 passage means communicating between said fourth and sixth conduitmeans,

(6) passage means communicating between said seven-th and eighth conduitmeans,

(7 passage means communicating between said eighth and tenth conduitmeans, with said first, second and third valve means in said secondvalve position,

(1) passage means communicating between said first conduit means andsaid second conduit means,

(2) passage means communicating between said third conduit means andsaid sampling means,

(3) passage means communicating between said fourth conduit means andsaid sampling means,

(4) passage means communicating 'between said fifth and sixth conduitmeans,

(5) passage means communicating between said third and seventh conduitmeans,

(6) passage means communicating between said fourth and eighth conduitmeans, and

(7) passage means communicating between said ninth and eighth conduitmeans.

2. The apparatus of claim 1 to include means for sequentiallypositioning said first, second and third valve means in said first andsecond valve positions.

3. Apparatus comprising a chromatographic column having an inlet end andan outlet end and containing a packing material that selectively retardsthe passage therethrough of a sample fluid directed to said column,means for measuring a property of an effluent withdrawn from said outletof said chromatographic column representative of the compositionthereof, a first, second and third valve means, each of said first,second and third valve means containing multiple ports andinterconnecting passages, said first valve means containing a samplingmeans, first conduit means communicating with said first valve means forpassing sample fluid thereto, second conduit means communicating withsaid first valve means for withdrawing sample fluid there-from, thirdconduit means communicating between said second valve means and saidfirst valve means, fourth conduit means communicating between said firstvalve means and said sec ond valve means, fifth conduit meanscommunicating with said second valve means for passing a first carriergas stream thereto, sixth conduit means communicating between said inletof said chromatographic column and said second valve means for passingsample fluid and carrier gas therethrough, seventh conduit meanscommunicating with said second valve means for withdrawing carrier gasand wash fluid therefrom, eighth conduit means communicating betweensaid second valve means and said third valve means, ninth conduit meanscommunicating with said third valve means for passing a second carriergas stream thereto, tenth conduit means communicating with said thirdvalve means for passing a Wash fluid thereto, each of said valve meanshaving a first and second valve position, with each of said first,second and third valve means in said first valve position,

(1) passage means communicating between said first conduit means andsaid sampling means,

(2) passage means communicating between said sampling means and saidsecond conduit means,

(3) passage means communicating between said fifth conduit means andsaid third conduit means,

(4) passage means communicating between said third and fourth conduitmeans,

(5) passage means communicating between said fourth and sixth conduitmeans,

(6) passage means communicating between said seventh and eighth conduitmeans,

(7 passage means communicating between said eighth and tenth conduitmeans,

'with said first, second and third valve means in said second valveposition,

(1) passage means communicating between said first conduit means andsaid second conduit means,

(2) passage means communicating between said third conduit means andsaid sampling means,

(3) passage means communicating betwene said fourth conduit means andsaid sampling means,

(4) passage means communicating between said fifth and sixth conduitmeans,

(5) passage means communicating between said third and seventh conduitmeans,

(6) passage means communicating between said fourth and eighth conduitmeans, and

(7) passage means communicating between said ninth and eighth conduitmeans.

4. The apparatus of claim 3 further comprising means for sequentiallypositioning said first, second, and third valve means in said first andsecond valve positions.

5. A method of analyzing a liquid containing at least one solublenon-volatile constituent comprising:

(a) passing said liquid through a sample trapping zone;

(b) trapping a portion of said liquid within said sample trapping zone;

(c) passing a carrier gas through said sample trapping zone to therebyvaporize volatile constituents of said liquid trapped in said zonethereby leaving a residue of said non-volatile constituents therein;

(d) passing said vaporized constituents to a chromatographic analysiszone;

(e) isolating said residue in said sample trapping zone while continuingthe passage of said vaporized constituents to said chromatographicanalysis zone by said carrier gas; and

(f) passing a wash solvent through said sample trapping zone to removesaid residue therefrom.

6. The method of claim 5 further comprising passing a drying gas throughsaid sample trapping zone after said 40 solvent is passed therethrough.

References Cited UNITED STATES PATENTS Breally et al.: Analyst, April1959, vol. 84, pp. 221- 225, copy in 7323.1.

Karasek et al.: I.S.A. Journal, vol. 7, No. 3, March 1960, pp. 70-71,copy in 7323.l.

RICHARD C. QUEISSER, Primary Examiner.

CHARLES A. RUEHL, Assistant Examiner.

